The present invention relates to peptide substances, their preparation and their use as complement inhibitors. In particular, these are substances having a guanidine or amidine radical as terminal group. In particular, the present invention relates to inhibitors of the complement proteases C1s and C1r.
The activation of the complement system leads, via a cascade of about 30 proteins, finally to, inter alia, the lysis of cells. At the same time, molecules which, like, for example, C5a, can lead to an inflammatory reaction are liberated. Under physiological conditions, the complement system provides defense against foreign bodies, e.g. viruses, fungi, bacteria and cancer cells. The activation by the various routes takes place initially via proteases. Activation enables these proteases to activate other molecules of the complement system, which in turn may be inactive proteases. Under physiological conditions, this systemxe2x80x94similarly to blood coagulationxe2x80x94is under the control of regulator proteins which counteract excessive activation of the complement system. In these cases, intervention to inhibit the complement system is not advantageous.
In some cases, however, the complement system overreacts and this contributes to the pathophysiology of disorders. In these cases, therapeutic intervention in the complement system by inhibition or modulation of the overshooting reaction is desirable. Inhibition of the complement system is possible at various levels in the complement system and by inhibition of various effectors. The literature contains examples of the inhibition of the serine proteases at the C1 level with the aid of the C1-esterase inhibitor as well as inhibition at the level of the C3- and C5-convertases with the aid of soluble complement receptor CR1 (sCR1), inhibition at the C5 level with the aid of antibodies and inhibition at the C5a level with the aid of antibodies or antagonists. The tools used for achieving the inhibition in the abovementioned examples are proteins. The present invention describes low molecular weight substances which are used for inhibiting the complement system.
In general activation of the complement system is to be expected in every inflammatory disorder which is associated with intrusion of neutrophilic blood cells. It is therefore expected that an improvement in pathophysiological status will be achieved in all these disorders by inhibiting parts of the complement system.
The activation of the complement is associated with the following disorders or pathophysiological conditions (Liszewski, M. K.; Atkinson, J. P.: Exp. Opin. Invest. Drugs 7(3) (1998): 324-332; Morgan, B. P.: Biochemical Society Transactions 24; (1996), 224-9; Morgan, B. P.: Critical Review in Clinical Laboratory Sciences 32 (3); (1995), 265-298; Hagmann, W. K.; Sindelar, R. D.: Annual reports in medicinal chemistry 27, (1992), 199 et seq.; Lucchesi, B. R.; Kilgore, K. S.: Immunopharmacology 38 (1997), 27-42; Makrides, S. C.: Pharmacological Reviews 50(1)(1998), 59-85)
Reperfusion injuries after ischemias; ischemic conditions, during, for example, operations with the aid of heart-lung machines; operations in which blood vessels are clamped off generally for avoiding major hemorrhages; myocardial infarction; thromboembolic cerebral infarction; pulmonary thrombosis, etc.;
Hyperacute organ rejection; especially in xenotransplantations;
Organ failure, e.g. multiple organ failure or ARDS (adult respiratory distress syndrome);
Disorders due to trauma (cranial trauma) or multiple injury, e.g. thermal injury (burns);
Anaphylactic shock;
Sepsis; xe2x80x9cvascular leak syndromexe2x80x9d: in the case of sepsis and after treatment with biological agents, such as interleukin-2 or after transplantation;
Alzheimer""s disease and other inflammatory neurological disorders, such as myastenia graevis, multiple sclerosis, cerebral lupus, Guillain-Barre syndrome; meningitis; encephalitis;
Systemic lupus erythematosus (SLE);
Rheumatoid arthritis and other inflammatory disorders of the rheumatoid disorder group, e.g. Behcet""s Syndrome; Juvenile rheumatoid arthritis;
Renal inflammations of various origin, e.g. Glomerulonephritis, Lupus nephriti; 
Pancreatitis;
Asthma; chronic bronchitis;
Complications during dialysis in the case of kidney failure;
Vasculitis; thyroiditis;
Ulcerative colitis and other inflammatory disorders of the gastrointestinal tract;
Autoimmune diseases.
It is possible that complement plays a role in spontaneous abortions, based on immunological rejection reactions (Giacomucci E., Bulletti C., Polli V., Prefetto R A., Flamigni C., Immunologically mediated abortion (IMA). Journal of Steroid Biochemistry and Molecular Biology, 49(2-3) (1994), 107-21). Here, it is possible that modulation of the immunological rejection reaction is achieved by inhibition of the complement system and hence the rate of abortions is correspondingly reduced.
Complement activation plays a role in the case of side effects of drugs. Liposome-based therapies which are used, for example, in cancer treatment may be mentioned as an example here. Hypersensitive reactions have been observed in patients who have been treated with drug formulations based on liposomes (Transfusion 37 (1997) 150). Activation of the complement system has also been demonstrated for other excipients used in drug formulations, e.g. Cremophor EL (Szebeni, J. et al. Journal of the National Cancer Institute 90 (4); 1998). The complement activation may therefore be responsible for the anaphylactoid reactions observed in some cases. Inhibition of the complement system, for example by the C1s inhibitors mentioned here, should therefore alleviate the side effects of medicaments based on activation of the complement system and reduce resulting hypersensitivity reactions.
In the abovementioned disorders, activation of the complement system has been demonstrated.
The synthesis of complement proteins in special diseased tissues or organs indicates participation of the complement system in the pathophysiology of these disorders. Thus, in the case of myocardial infarction, vigorous further synthesis of many complement proteins in the myocardium was detected (Yasojima, K.; Schwab, C.; McGeer, E. G.; McGeer, P. L.; Circulation Research 83 (1998), 860-869). This was also detected in inflammatory disorders of the brain, e.g. multiple sclerosis and bacterial meningitis, and in colitis.
Evidence that complement activation has taken place can be provided by detecting the cell lysis complex in the tissue and by detecting soluble SC5b-9 or other activation products of complement, e.g. factor Bb, C3a; C4a, C5a; C3b, C3d; etc., in the plasma. By corresponding tests, it was possible to demonstrate, inter alia, participation of the complement system in the atherosclerosis as well as to show a relationship with myocardial infarction, unstable angina pectoris and organ transplantations, to mention but a few examples.
Raised blood levels of complement proteins, such as C3 or C4, are correlated with various cardiovascular disorders, e.g. heart failure, as well as diabetes. A similar relationship has imposulated for an increase in TNF in the case of heart failure. Initial studies on the treatment of heart failure with TNF inhibitors (soluble TNF receptor, antibodies) were rated positively. TNF is secreted, for example, after stimulation by complement factor C5a. It has been possible to show that inhibition of the C5a action prevents release of TNF (XVII International Complement Workshop, P. Ward, Abstract 324 in Molecular Immunology 35 (411 6-7), 1998). Accordingly, a treatment of disorders, in which raised levels of complement proteins are present, with the inhibitors described in this publication is possible, as the treatment of disorders in which raised levels of TNF are present.
Furthermore, the participation of complement has been demonstrated in the case of (Atherosclerosis 132 (1997); 131-138. Particular complications due to rapid atherosclerotic processes occur, for example, in organs after transplantations. These processes are the most frequent reason for the chronic failure of the transplanted organs in clinical medicine. In future, apart from transplantations of human organs (allotransplantations) uses of transplants from other species (xenotransplants) has also been considered.
Accordingly, the treatment of the abovementioned disorders or pathophysiological conditions with complement inhibitors is desirable, in particular the treatment with low molecular weight inhibitors.
FUT and FUT derivatives are amidinophenolic esters and amidinonaphthol esters and are described as complement inhibitors (e.g. Immunology 49(4) (1983), 685-91).
Serine proteases are present in the complement system in the three different activation routes: the traditional, alternative and MBL route (Arlaud, G. J. et al. Advances in Immunology 69; (1998) 249 et seq.). In their respective routes, they play a decisive role at the beginning of the cascade.
Inhibitors of the corresponding serine proteases can intervene here both in a completely inhibitory manner and in a modulating manner (partial inhibition) if the complement has been pathophysiologically activated.
Some proteases of the various activation routes are particularly suitable for inhibiting the complement system. From the class of the thrombin-like serine proteases these are the complement proteases C1r and C1s in the traditional route, factor D and factor B in the alternative route and MASP I and MASP II in the MBL route. Inhibition of these proteases then leads to restoration of physiological control of the complement system in the abovementioned disorders or pathophysiological conditions.
The traditional route of the complement system is usually activated by means of antibodies which have bound to an antigen. In physiological conditions this route of the complement system helps in the defense against foreign bodies which are recognized by antibodies. However, an overreaction leads to injuries in the tissue and the body. These injuries can be prevented by inhibiting of the traditional route. According to present knowledge, activation of the complement system via antibodies is experienced during hyperacute organ rejection and especially in the case of xenotransplantations; in the case of reperfusion injuries after ischemias (possibly via IgM antibodies and a neoepitope; Literature: Journal of Exp. Med. 183, (1996), 2343-8; Carroll, XVII International Complement Workshop, Rhodes 1998), for example in the case of myocardial infarction, other thrombotic disorders or long-term vascular occlusions, as are usual, for example, during operations; in the case of anaphylactic shock; in the case of sepsis; in the case of SLE; in the case of disorders in the area of rheumatoid arthritis, renal inflammations of various origins; vasculitis, all autoimmune diseases and allergies. In general, injuries in various organs due to activation of the complement system are to be expected in the case of every disorder in which circulating immune complexes are present. A part of the invention is to prevent these injuries by the C1-inhibitors described.
Activation of the complement system by the traditional route takes place under pathophysiological conditions partly with circumvention of antibodies. Examples of this are Alzheimer""s disease, and the unspecified activation of this route by other proteases, as occur, for example, in the lysis therapy following myocardial infarction. In these cases, too, limitation of the injury to be achieved with the C1 inhibitors described.
The activation of the classical route has been demonstrated, for example, by the detection of the activated proteins, for example C1q in the affected tissue (e.g. Circulation Research 83; (1998) 860). However, the pathophysiological participation of the complement system is more substantial if inhibitors which inhibit only the traditional route in the complement system are used. A physiological inhibitor for this purpose is the C1-esterase inhibitor (protein is described in The Complement System, Rother, Till, Hxc3xa4nsch eds.; Springer; 1998; pages 353 et seq.). With the aid of this inhibitor, participation of the traditional route and the possibility of therapeutic intervention have been demonstrated in experiments. Some references are given in more detail below:
1. Bauernschmitt R. Bohrer H. Hagl S. Rescue therapy with C1-esterase inhibitor concentrate after emergency coronary surgery for failed PTCA. Intensive Care Medicine. 24(6): (1998), 635-8.
2. Khorram-Sefat R. Goldmann C. Radke A. Lennartz A. Mottaghy K. Afify M. Kupper W. Klosterhalfen B. The therapeutic effect of C1-inhibitor on gut-derived bacterial translocation after thermal injury. Shock. 9(2): (1998) 101-8.
3. Niederau C. Brinsa R. Niederau M. Luthen R. Strohmeyer G. Ferrell L D. Effects of C1-esterase inhibitor in three models of acute pancreatitis. International Journal of Pancreatology. 17(2): (1995) 189-96.
4. Hack C E. Ogilvie A C. Eisele B. Jansen P M. Wagstaff J. Thijs L G. Initial studies on the administration of C1-esterase inhibitor to patients with septic shock or with a vascular leak syndrome induced by interleukin-2 therapy. Progress in Clinical and Biological Research. 388: (1994), 335-57.
5. Dalmasso A P. Platt J L. Prevention of complement-mediated activation of xenogeneic endothelial cells in an in vitro model of xenograft hyperacute rejection by C1 inhibitor. Transplantation. 56(5): (1993), 1171-6.
6. Nurnberger W. Michelmann I. Petrik K. Holthausen S. Willers R. Lauermann G. Eisele B. Delvos U. Burdach S. Gobel U. Activity of C1 esterase inhibitor in patients with vascular leak syndrome after bone marrow transplantation. Annals of Hematology. 67(1): (1993), 17-21.
7. Buerke M. Prufer D. Dahm M. Oelert H. Meyer J. Darius H. Blocking of classical complement pathway inhibits endothelial adhesion molecule expression and preserves ischemic myocardium from reperfusion injury. Journal of Pharmacology and Experimental Therapeutics. 286(1): (1998), 429-38.
8. Nissen M H. Bregenholt S. Nording J A. Claesson M H. C1-esterase inhibitor blocks T lymphocyte proliferation and cytotoxic T lymphocyte generation in vitro. International Immunology. 10(2): (1998), 167-73.
9. Salvatierra A. Velasco F. Rodriguez M. Alvarez A. Lopez-Pedrera R. Ramirez R. Carracedo J. Lopez-Rubio F. Lopez-Pujol A. Guerrero R. C1-esterase inhibitor prevents early pulmonary dysfunction after lung transplantation in the dog. American Journal of Respiratory and Critical Care Medicine. 155(3): (1997), 1147-54.
10. Horstick G. Heimann A. Gotze O. Hafner G. Berg O. Boehmer P. Becker P. Darius H. Rupprecht H J. Loos M. Bhakdi S. Meyer J. Kempski O. Intracoronary application of C1 esterase inhibitor improves cardiac function and reduces myocardial necrosis in an experimental model of ischemia and reperfusion. Circulation. 95(3): (1997), 701-8.
11. Heckl-Ostreicher B. Wosnik A. Kirschfink M. Protection of porcine endothelial cells from complement-mediated cytotoxicity by the human complement regulators CD59, C1 inhibitor, and soluble complement receptor type 1. Analysis in a pig-to-human in vitro model relevant to hyperacute xenograft rejection. Transplantation. 62(11): (1996), 1693-6.
12. Niederau C. Brinsa R. Niederau M. Luthen R. Strohmeyer G. Ferrell L D. Effects of C1-esterase inhibitor in three models of acute pancreatitis. International Journal of Pancreatology. 17(2): (1995), 189-96.
13. Buerke M. Murohara T. Lefer A M. Cardioprotective effects of a C1 esterase inhibitor in myocardial ischemia and reperfusion circulation. 91(2): (1995), 393-402.
14. Hack C E. Ogilvie A C. Eisele B. Jansen P M. Wagstaff J. Thijs L G. Initial studies on the administration of C1-esterase inhibitor to patients with septic shock or with a vascular leak syndrome induced by interleukin-2 therapy. Progress in Clinical and Biological Research. 388: (1994), 335-57.
15. Dalmasso A P. Platt J L. Prevention of complement-mediated activation of xenogeneic endothelial cells in an in vitro model of xenograft hyperacute rejection by C1 inhibitor. Transplantation. 56(5): (1993), 1171-6.
16. Guerrero R. Velasco F. Rodriguez M. Lopez A. Rojas R. Alvarez M A. Villalba R. Rubio V. Torres A. del Castillo D. Endotoxin-induced pulmonary dysfunction is prevented by C1-esterase inhibitor. Journal of Clinical Investigation. 91(6): (June 1993), 2754-60.
Inhibitors which inhibit C1s and/or C1r but not factor D are desirable. Preferably, MASP-I and lysis enzymes, such as t-PA and plasmin, should not be inhibited.
A hereditary disease, hereditary angioneurotic edema, which is due to a deficiency of C1-esterase inhibitor is usually treated by administering C1-esterase inhibitor. Treatment with the C1 inhibitors described here, under certain circumstances as additional medication, is likewise an application of this invention.
Substances which effectively inhibit C1s and C1r are particularly preferred.